<PackageReference Include="System.Configuration.ConfigurationManager" Version="10.0.2" />

System.Configuration.Provider.ProviderCollection

Represents a collection of provider objects that inherit from ProviderBase.
namespace System.Configuration.Provider { public class ProviderCollection : ICollection, IEnumerable { public ProviderBase this[string name] { get; } public int Count { get; } public bool IsSynchronized { get; } public object SyncRoot { get; } public ProviderCollection(); public IEnumerator GetEnumerator(); public virtual void Add(ProviderBase provider); public void Remove(string name); public void SetReadOnly(); public void Clear(); public void CopyTo(ProviderBase[] array, int index); } }